Process for the Preparation of Defined Functional Lactic Acid Oligomers

ABSTRACT

A process for manufacturing defined functional lactic acid oligomers, can include contacting lactide with at least one compound that is a transfer agent. Oligomers can be prepared according to the process.

FIELD OF THE INVENTION

The present invention is in the field of processes for the manufactureof defined functional lactic acid oligomers, in particular, bycontacting lactide with at least one compound that is a transfer agent.It also relates to oligomers prepared according to the process.

BACKGROUND OF THE INVENTION

Lactic acid oligomers are commonly utilised as intermediates in thesynthesis of high molecular weight poly(lactic acid) products. There ishowever also a growing interest for lactic acid oligomers as such. Theyreceive special attention in the field of medical applications forinstance for the production of implantable medical devices andscaffolds. Because of their intrinsic properties and theirbiological-based character they can be also used in added-value domainssuch as

-   -   a substitute for waxes, oils and oligomers currently used in the        pharmaceutical formulation domain,    -   macromers (building blocks) for the polymerisation or        copolymerisation of new and existing polymers,    -   new products in such sectors as binding agents, plasticisers,        adhesives, lubricants, inks, nucleating agents, compatibiliser,        etc. where physical and chemical properties are key parameters        to the performance of the material and are achieved by tailoring        the material at molecular scale. Lactic acid oligomers are        usually composed of a few and limited number of lactic acid        units and can be obtained by polycondensation methods: the        hydroxyl and carboxylic acid groups of lactic acid react        together and removal of the water formed during this        condensation reaction results in the formation of longer        polymeric chains of lactic acid.

The main drawback of this process is the occurrence of numerouscompetitive reactions resulting in significant amounts of structurallyunclear components. Transesterification reactions, both inter andintramolecular, can occur during the polycondensation. Impurities suchas carboxylic acids (e.g. formic acid, acetic acid, propionic acid etc .. . ) or alcohols (e.g. methanol, ethanol, propanol etc . . . ) in themonomer (lactic acid) can act as chain terminators. Therefore, polymersof different sizes with linear, branched or ring structures might beformed.

The polycondensation of lactic acid is a step-growth reaction thatresults in carboxylic acid and alcoholic end-groups (di-end-functionalpolymers). Without further modification of the end-groups, the use ofPLA oligomers as building blocks is therefore limited. For exampletelechelic PLA-diol receives a growing interest for the production ofcopolymers (amongst other with polyethylene glycol or with diisocyanateto form polyurethanes) cannot be produced directly by polycondensation.

The present invention aims to overcome the problems of the art beproviding a new technique for producing well-defined functional lacticacid oligomers from lactide.

SUMMARY OF THE INVENTION

The present invention relates to a process for the manufacture of alactic acid oligomer comprising the steps of: contacting lactide in thepresence of a catalyst with at least one compound, wherein said compoundis a polymer selected from the group comprising of polypropylene,polyethylene, poly (L) lactic acid, poly (D) lactic acid, poly (D,L)lactic acid, polysiloxane, polybutylene succinate, polytrimethylenecarbonate, polycaprolactone, polyester, polyether, polyolefin,polystyrene, polyisoprene, polycarbonate, polyalkylenecarbonate,polyamine, polyamide, polyvinyl alcohol, polyurethane, and polyacrylate,and containing n number of OH and/or NH₂ group(s), where n is an integergreater than or equal to 1, and wherein

${\frac{{Moles}\mspace{14mu} {of}\mspace{14mu} {Lactide}}{\left( {{Moles}\mspace{14mu} {of}\mspace{14mu} {Compound}*n} \right)} \leq 70},$

and wherein the reaction is performed at a temperature of at least 70°C.

The process may be performed with or without solvent.

The catalyst employed by the process may have general formula M(Y¹,Y², .. . Y^(p))_(q), in which M is a metal selected from the group comprisingthe elements of columns 3 to 12 of the periodic table of the elements,as well as the elements Al, Ga, In, Tl, Ge, Sn, Pb, Sb, Ca, Mg and Bi;whereas Y¹, Y², . . . Y^(p) are each substituents selected from thegroup comprising alkyl with 1 to 20 carbon atoms, aryl having from 6 to30 carbon atoms, alkoxy having from 1 to 20 carbon atoms, aryloxy havingfrom 6 to 30 carbon atoms, and other oxide, carbon/late, and halidegroups as well as elements of group 15 and/or 16 of the periodic table;p and q are integers between 1 and 6.

The catalyst may have a general formula (III):

wherein

R² and R³ are each independently C₁₋₁₀alkyl,

R⁴, R⁵ and R⁶ are each independently C₁₋₁₀alkyl, or

R⁴ and R⁵ are covalently bound to each other and are each a methyleneand

R⁶ is C₁₋₁₀alkyl,

X² is selected from C₁₋₁₀alkyl, —OR⁷, or —N(SiR⁸ ₃)₂, R⁷ is C₁₋₁₀alkyl,and R⁸ is C₁₋₆alkyl.

X¹ may be NH₂. X¹ may be OH. n may be at least 2

R¹ wherein may be selected from ethyl, propyl, prop-2-yl, or octyl. R¹may be propyl and n is 1,or R¹ may be prop-2-yl and n is 3, or R¹ may beethyl and n is 2.

R¹ may be selected from prop-2-enecarbonyloxyethyl,prop-2-enecarbonyloxypropyl, prop-2-enecarbonyloxymethyl,ethylenecarbonyloxymethyl, ethylenecarbonyloxyethyl, orethylenecarbonyloxypropyl.

R¹ may be selected from C₆-C₈arylC₁-C₄alkyl, C₆-C₈arylC₁-C₂alkyl orbenzyl.

The number average molecular weight of the lactic acid oligomer asmeasured by size exclusion chromatography minus the molecular weight thecompound divided by n may be equal to or below 10 100 g/mol,

${\frac{{{Mn}\left( {{lactic}\mspace{14mu} {acid}\mspace{14mu} {oligomer}} \right)} - {{Mw}({compound})}}{n} \leq {10\; 100\; g\text{/}{mol}}},$

wherein Mn(lactic acid oligomer) is measured by size exclusionchromatography, and wherein n is number of OH and NH2 groups present inthe compound.

The at least one compound may be a mixture of at least two of thepolymers.

The invention also relates to an oligomer prepared according to theprocess of the invention.

DESCRIPTION OF THE FIGURES

FIG. 1 is a presentation of the DSC curve for PP/PLA blend (50/50).

FIG. 2 is a presentation of the DSC curve PP/PLA/PP-PLA blend(40/40/10).

FIG. 3 is a presentation of the SEM picture of blend PP/PLA 50/50.

FIG. 4 is a presentation of the SEM picture of blend PP/PLA/PP-PLA40/40/10.

DETAILED DESCRIPTION OF THE INVENTION

Unless otherwise defined, all terms used in disclosing the invention,including technical and scientific terms, have the meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. By means of further guidance, term definitions are includedbelow to better appreciate the teaching of the present invention.

Before the present process or products of the invention is described, itis to be understood that this invention is not limited to particularprocesses or products described, as such processes or products may, ofcourse, vary. It is also to be understood that the terminology usedherein is not intended to be limiting, since the scope of the presentinvention will be limited only by the appended claims.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the present invention. Thus, appearances of the phrases“in one embodiment” or “in an embodiment” in various places throughoutthis specification are not necessarily all referring to the sameembodiment, but may. Furthermore, the particular features, structures orcharacteristics may be combined in any suitable manner, as would beapparent to a person skilled in the art from this disclosure, in one ormore embodiments. Furthermore, while some embodiments described hereininclude some but not other features included in other embodiments,combinations of features of different embodiments are meant to be withinthe scope of the invention, and form different embodiments, as would beunderstood by those in the art. For example, in the following claims,any of the claimed embodiments can be used in any combination.

As used herein, the singular forms “a”, “an”, and “the” include bothsingular and plural referents unless the context clearly dictatesotherwise.

The terms “comprising”, “comprises” and “comprised of” as used hereinare synonymous with “including”, “includes” or “containing”, “contains”,and are inclusive or open-ended and do not exclude additional,non-recited members, elements or method steps. Where reference is madeto embodiments as comprising certain elements or steps, this impliesthat embodiments are also envisaged which consist essentially of therecited elements or steps.

The recitation of numerical ranges by endpoints includes all numbers andfractions subsumed within the respective ranges, as well as the recitedendpoints.

All documents cited in the present specification are hereby incorporatedby reference in their entirety.

The present invention discloses a process for obtaining well-definedlactic acid oligomers in terms of molecular weight control, chain endcontrol and structure control. Structure control refers to the linearityor branching, and sequence distribution in the case of copolymers.

In particular the present invention provides a process for themanufacture of a lactic acid oligomer comprising the steps of:contacting lactide in the presence of a catalyst with at least onecompound, wherein said compound is a polymer selected from the groupcomprising of polypropylene, polyethylene, poly (L) lactic acid, poly(D) lactic acid, poly (D,L) lactic acid, polysiloxane, polybutylenesuccinate, polytrimethylene carbonate, polycaprolactone, polyester,polyether, polyolefin, polystyrene, polycarbonate,polyalkylenecarbonate, polyamine, polyamide, polyvinyl alcohol,polyurethane, and polyacrylate, and containing n number of OH and/or NH₂group(s), where n is an integer greater than or equal to 1, and wherein

${\frac{{Moles}\mspace{14mu} {of}\mspace{14mu} {Lactide}}{\left( {{Moles}\mspace{14mu} {of}\mspace{14mu} {Compound}*n} \right)} \leq 70},$

and wherein the reaction is performed at a temperature of at least 70°C.

By the term at least one compound is meant one or more compound(s)selected from the defined list of compounds. A compound according to oneaspect of the present invention is a polymer. The at least one compoundcan be a mixture of at least two of the polymers selected from thedefined list of polymers. Therefore, if more than one compound (polymer)is used, it is meant that compounds are different compounds (differentpolymers), and selected from the defined list of compounds (polymers).

In an embodiment a compound used in the process according to the presentinvention may be a polymer selected from the group comprisingpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polyolefin, polystyrene, polycarbonate,polyalkylenecarbonate, polyvinyl alcohol, polyurethane, andpolyacrylate, and containing n number of OH and/or NH₂ group(s), where nis an integer greater than or equal to 1.

In an embodiment a compound used in the process according to the presentinvention may be a polymer selected from the group comprising ofpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polystyrene, polycarbonate,polyalkylenecarbonate, polyvinyl alcohol, polyurethane, andpolyacrylate, and containing n number of OH and/or NH₂ group(s), where nis an integer greater than or equal to 1.

In an embodiment a compound used in the process according to the presentinvention may be a polymer that is polypropylene containing n number ofOH and/or NH₂ group(s), where n is an integer greater than or equalto 1. The polymer may be polypropylene containing n number of OH groups,where n is an integer greater than or equal to 1. The reaction may beperformed in solvent. The reaction may be performed at a temperature of90° C. -120° C.

In an embodiment a compound used in the process according to the presentinvention may be a polymer selected from the group comprising ofpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polyolefin, polystyrene, polycarbonate,polyalkylenecarbonate, polyvinyl alcohol, polyurethane, andpolyacrylate, and containing n number of OH and/or NH₂ group(s), where nis an integer greater than or equal to 1, and the reaction is performedwith solvent at a temperature of at least 90° C., preferably 90-120° C.using a catalyst of the general formula M(Y¹,Y², . . . Y^(p))_(q).

In an embodiment a compound used in the process according to the presentinvention may be a polymer selected from the group comprising ofpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polyolefin, polystyrene, polycarbonate,polyalkylenecarbonate, polyvinyl alcohol, polyurethane, andpolyacrylate, and containing n number of OH and/or NH₂ group(s), where nis an integer greater than or equal to 1, and the reaction is performedwithout solvent at a temperature of at least 110° C., preferably 140°C.-190° C. using a catalyst of the general formula M(Y¹,Y², . . .Y^(p))_(q).

In an embodiment a compound used in the process according to the presentinvention may be a polymer selected from the group comprising ofpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polyolefin, polystyrene, polycarbonate,polyalkylenecarbonate, polyvinyl alcohol, polyurethane, andpolyacrylate, and containing n number of OH and/or NH₂ group(s), where nis an integer greater than or equal to 1, and the reaction is performedwith solvent at a temperature of at least 70° C., preferably 90-120° C.using a catalyst of the general formula (III).

In an embodiment a compound used in the process according to the presentinvention may be a polymer selected from the group comprising ofpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polyolefin, polystyrene, polycarbonate,polyalkylenecarbonate, polyvinyl alcohol, polyurethane, andpolyacrylate, and containing n number of OH and/or NH₂ group(s), where nis an integer greater than or equal to 1, and the reaction is performedwithout solvent at a temperature of at least 110° C., preferably atleast 140° C., preferably 140° C.-190° C. using a catalyst of thegeneral formula (III).

In an embodiment a compound used in the process according to the presentinvention may be a polymer selected from the group comprisingpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polyolefin, polystyrene, polycarbonate,polyalkylenecarbonate, polyamine, polyamide, polyvinyl alcohol,polyurethane, polyacrylate and polyaminoacid, and containing n number ofOH group(s), where n is an integer greater than or equal to 1, and thereaction is performed with or without solvent at a temperature of atleast 140° C. and using a organometallic catalyst or a catalyst of thegeneral formula M(Y¹,Y², . . . Y^(p))_(q).

In an embodiment a compound used in the process according to the presentinvention may be a polymer selected from the group comprisingpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polycaprolactone, polyester, polyether,polyolefin, polystyrene, polyisoprene, polycarbonate,polyalkylenecarbonate, polyamine, polyamide, polyvinyl alcohol,polyurethane, polyacrylate and polyaminoacid, and containing n number ofNH₂ group(s), where n is an integer greater than or equal to 1, and thereaction is performed with or without solvent at a temperature of atleast 140° C. and using a organometallic catalyst or a calatyst of thegeneral formula M(Y¹,Y², . . . Y^(p))_(q).

In an embodiment a a compound used in the process according to thepresent invention may be a polymer selected from the group comprisingpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polycaprolactone, polyester, polyether,polyolefin, polystyrene, polyisoprene, polycarbonate,polyalkylenecarbonate, polyamine, polyamide, polyvinyl alcohol,polyurethane, polyacrylate and polyaminoacid, and containing n number ofNH₂ and OH group(s), where n is an integer greater than or equal to 2and the reaction is performed with or without solvent at a temperatureof at least 140° C. and using a organometallic catalyst or a calatyst ofthe general formula M(Y¹,Y², . . . Y^(p))_(q).

In an embodiment a compound used in the process according to the presentinvention may be a polymer selected from the group comprisingpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polyolefin, polystyrene, polycarbonate,polyalkylenecarbonate, polyamine, polyamide, polyvinyl alcohol,polyurethane, polyacrylate and polyaminoacid, and containing n number ofOH group(s), where n is an integer greater than or equal to 1, and thereaction is performed with or without solvent at a temperature of atleast 110° C. and using a organometallic catalyst or using a catalystthe general formula (III).

In an embodiment a compound used in the process according to the presentinvention may be a polymer selected from the group comprisingpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polycaprolactone, polyester, polyether,polyolefin, polystyrene, polyisoprene, polycarbonate,polyalkylenecarbonate, polyamine, polyamide, polyvinyl alcohol,polyurethane, polyacrylate and polyaminoacid, and containing n number ofNH₂ group(s), where n is an integer greater than or equal to 1, and thereaction is performed with or without solvent at a temperature of atleast 110° C. and using a organometallic catalyst or using a catalystthe general formula (III).

In an embodiment a compound used in the process according to the presentinvention may be a polymer selected from the group comprisingpolypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polysiloxane, polybutylene succinate,polytrimethylene carbonate, polycaprolactone, polyester, polyether,polyolefin, polystyrene, polyisoprene, polycarbonate,polyalkylenecarbonate, polyamine, polyamide, polyvinyl alcohol,polyurethane, polyacrylate and polyaminoacid, and containing n number ofNH₂ and OH group(s), where n is an integer greater than or equal to 2and the reaction is performed with or without solvent at a temperatureof at least 110° C. and using a organometallic catalyst or using acatalyst the general formula (III).

In particular, the present invention provides a process for themanufacture of a lactic acid oligomer comprising the step of contactinglactide with at least one compound that is a transfer agent, in thepresence of a catalyst wherein the mole ratio of lactide to (compound.n)is equal to or below 70, wherein compound.n refers to the moles ofcompound multiplied by the total number (n) of OH and/or NH₂ groups inthe compound, wherein the reaction is performed at a temperature of 110°C. to 190° C. without solvent, wherein the compound is a polymerselected from the group comprising polyolefin, polyester, polycarbonate,polypropylene, polyethylene, poly (L) lactic acid, poly (D) lactic acid,poly (D,L) lactic acid, polybutylene succinate, polytrimethylenecarbonate, polyalkylenecarbonate, polysiloxane, polyether, polystyrene,polyisoprene, polyamine, polyamide, polyvinyl alcohol, polyurethane,polyacrylate and polyaminoacid, and containing n number of OH and/or NH₂group(s), where n is an integer greater than or equal to 1. The productmay be referred to as a co-polymer of the lactide monomer and thepolymer.

The present invention also provides a process for the manufacture of alactic acid oligomer comprising the step of contacting lactide with atleast one compound that is a transfer agent, in the presence of acatalyst wherein the mole ratio of lactide to compound.n is equal to orbelow 70, wherein compound.n refers to the number of moles of compoundmultiplied by the total number of OH and/or NH₂ groups in the compound,and wherein the reaction is performed at a temperature of at least 70°C., preferably at least 90° C., preferably at least 105° C., wherein thecompound has formula (I)

wherein X¹ is OH or NH₂, n is an integer selected from 1, 2, 4, 5, 6, 7,8, 9,or 10 or is 1 to 10, and R¹ is a group selected from C₁-C₂₀alkyl;C₃-C₈cycloalkyl; C₂-C₂₀alkenyl; C₂-C₂₀alkynyl;C₂-C₁₀alkenylcarbonyloxyC₁-C₁₀alkyl; heterocycylC₁-C₆alkyl;hydroxylcarbonylC₁-C₁₀₀alkyl;C₆-C₁₀arylC₁-C₆alkyloxycarbonylaminoC₁-C₁₀alkyl; aminoC₁-C₁₀alkyl;haloC₁-C₁₀alkylcarbonyloxyC₁-C₁₀alkyl; hydroxyC₁-C₁₀alkyl; heterocycyl;C₆-C₁₀arylC₁-C₆alkyl; each group being optionally substituted by one ormore substituents selected from C₁-C₆alkyl, hydroxyl, oxo, or whereinsaid at least one carbon atom in the heterocyclyl is optionallysubstituted by one or more oxo group, or wherein at least one nitrogenatom in the heterocyclyl is optionally substituted by an oxyl freeradical.

The term “alkyl” by itself or as part of another substituent, refers toa straight or branched saturated hydrocarbon group joined by singlecarbon-carbon bonds having 1 to 100 carbon atoms, for example 1 to 20carbon atoms, for example 1 to 6 carbon atoms, preferably 1 to 3 carbonatoms. When a subscript is used herein following a carbon atom, thesubscript refers to the number of carbon atoms that the named group maycontain.

Thus, for example, C₁₋₁₀₀alkyl, means an alkyl group of 1 to 100 carbonatoms, for example 1 to 75 carbon atoms, for example 1 to 50 carbonatoms, for example 1 to 25 carbon atoms, for example 1 to 20 carbonatoms, for example 1 to 10 carbon atoms, more preferably 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 carbon atoms.

Thus, for example, C₁₋₂₅alkyl, means an alkyl group of 1 to 25 carbonatoms, preferably from 3 to 15 carbon atoms, more preferably 3, 4, 5, 6,7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25carbon atoms.

Thus, for example, C₁₋₂₀alkyl, means an alkyl group of 1 to 20 carbonatoms, preferably from 3 to 15 carbon atoms, more preferably 3, 4, 5, 6,7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 carbon atoms.

Thus, for example, C₁₋₁₅alkyl, means an alkyl group of 1 to 15 carbonatoms, preferably from 3 to 15 carbon atoms, more preferably 3, 4, 5, 6,7, 8, 9, 10, 11, 12, 13, 14, 15 carbon atoms.

Thus, for example, C₁₋₁₀alkyl, means an alkyl group of 1 to 10 carbonatoms, preferably from 3 to 10 carbon atoms, more preferably 3, 4, 5, 6,7, 8, 9, 10 carbon atoms.

Thus, for example, C₁₋₈alkyl, means an alkyl group of 1 to 8 carbonatoms, preferably from 3 to 8 carbon atoms, more preferably 3, 4, 5, 6,7, 8 carbon atoms.

Thus, for example, C₁₋₆alkyl means an alkyl of 1 to 6 carbon atoms,preferably from 2 to 6 carbon atoms, more preferably 2, 3, 4, 5, 6carbon atoms.

Thus, for example, C₁₋₄alkyl means an alkyl of 1 to 4 carbon atoms,preferably from 2 to 4 carbon atoms, more preferably 2, 3 or 4 carbonatoms.

Alkyl groups may be linear, or branched and may be substituted asindicated herein.

Alkyl includes all linear, or branched alkyl groups. Alkyl includes, forexample, methyl, ethyl, n-propyl, i-propyl, 2-methyl-ethyl, butyl andits isomers (e.g. n-butyl, i-butyl and t-butyl); pentyl and its isomers,hexyl and its isomers, heptyl and its isomers, octyl and its isomers,nonyl and its isomers, decyl and its isomers and the like.

The term “C₃₋₈cycloalkyl”, by itself or as part of another substituent,refers to a saturated or partially saturated cyclic alkyl containingfrom about 3 to about 8 carbon atoms. Examples of monocyclicC₃₋₈cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, orcyclohexyl.

Whenever the term “substituted” is used in the present invention, it ismeant to indicate that one or more hydrogens on the atom indicated inthe expression using “substituted” is replaced with a selection from theindicated group, provided that the indicated atom's normal valency isnot exceeded, and that the substitution results in a chemically stablesubstance, i.e. a substance that is sufficiently robust to surviveisolation to a useful degree of purity from a reaction mixture.

The term “alkenyl” by itself or as part of another substituent, refersto an unsaturated hydrocarbyl group, which may be linear, or branched,comprising one or more carbon-carbon double bonds having 2 to 20 carbonatoms, for example 2 to 18 carbon atoms, for example 2 to 16 carbonatoms, for example 2 to 15 carbon atoms, for example 2 to 14 carbonatoms, for example 2 to 12 carbon atoms, for example 2 to 10 carbonatoms, for example 2 to 8 carbon atoms, for example 2 to 6 carbon atoms,for example 2 to 4 carbon atoms. When a subscript is used hereinfollowing a carbon atom, the subscript refers to the number of carbonatoms that the named group may contain.

Thus, for example, C₂₋₂₀alkenyl means an alkenyl group of 2 to 20 carbonatoms, preferably 2 and 14 carbon atoms. Thus, for example, C₂₋₁₈alkenylmeans an alkenyl group of 2 to 18 carbon atoms, preferably 2 to 12carbon atoms. Thus, for example, C₂₋₁₆alkenyl means an alkenyl group of2 to 16 carbon atoms, preferably 2 to 10 carbon atoms. Thus, forexample, C₂₋₁₅alkenyl means an alkenyl group of 2 to 15 carbon atoms,preferably 2 to 10 carbon atoms. Thus, for example, C₂₋₁₄alkenyl meansan alkenyl group of 2 to 14 carbon atoms, preferably 2 to 10 carbonatoms. Thus, for example, C₂₋₁₂alkenyl means an alkenyl group of 2 to 12carbon atoms, preferably 2 to 8 carbon atoms. Thus, for example,C₂₋₁₀alkenyl means an alkenyl group of 2 to 10 carbon atoms, preferably2 to 6 carbon atoms. Thus, for example, C₂₋₈alkenyl means an alkenylgroup of 2 to 8 carbon atoms, preferably 2 to 6 carbon atoms. Thus, forexample, C₂₋₆alkenyl means an alkenyl group of 2 to 6 carbon atoms,preferably 2 to 5 carbon atoms. Thus, for example, C₂₋₄alkenyl means analkenyl group of 2 to 4 carbon atoms, preferably 2 or 3 carbon atoms.Non-limiting examples of alkenyl groups include ethenyl, 2-propenyl,2-butenyl, 3-butenyl, 2-pentenyl and its chain isomers, 2-hexenyl andits chain isomers, 2,4-pentadienyl and the like.

The term “C₂₋₂₀alkynyl” by itself or as part of another substituent,refers to an unsaturated hydrocarbyl group, which may be linear, orbranched, comprising one or more carbon-carbon triple bonds. When asubscript is used herein following a carbon atom, the subscript refersto the number of carbon atoms that the named group may contain.

Preferred alkynyl groups thus comprise 2 to 20 carbon atoms, forexample, 2 to 14 carbon atoms, for example 2 to 8. Non limiting examplesof alkynyl groups include ethynyl, 2-propynyl, 2-butynyl, 3-butynyl,2-pentynyl and its chain isomers, 2-hexynyl and its chain isomers andthe like.

The term “aryl”, as a group or part of another substituent, refers to apolyunsaturated, aromatic hydrocarbyl group having a single ring (i.e.phenyl) or multiple aromatic rings fused together (e.g. naphthalene), orlinked covalently, typically containing 6 to 30 atoms; wherein at leastone ring is aromatic. When a subscript is used herein following a carbonatom, the subscript refers to the number of carbon atoms that the namedgroup may contain. Thus, for example, C₆₋₃₀aryl means an aryl group of 6to 30 carbon atoms, preferably 6 to 20 carbon atoms. Thus, for example,C₆₋₁₂aryl means an aryl group of 6 to 12 carbon atoms, preferably 6 to10 carbon atoms. Thus, for example, C₆₋₁₀aryl means an aryl group of 6to 10 carbon atoms, preferably 6 to 8 carbon atoms. Thus, for example,C₆₋₈aryl means an aryl group of 6 to 8 carbon atoms. Thus, for example,C₆₋₇aryl means an aryl group of 6 to 7 carbon atoms. Non-limitingexamples of an aryl comprise phenyl, biphenylyl, biphenylenyl, or 1-or2-naphthanelyl.

The term “C₆₋₁₀arylC₁₋₆alkyl”, as a group or as part of anothersubstituent, means a C_(1— 6)alkyl as defined herein, wherein a hydrogenatom is replaced by a C₆₋₁₀aryl as defined herein. Examples of aralkylinclude benzyl, phenethyl, dibenzylmethyl, methylphenylmethyl,3-(2-naphthyl)-butyl, and the like.

The term “hydroxyC₁₋₁₀alkyl”, by itself or as part of anothersubstituent, represents a group of Formula —R^(e)—OH, wherein Re isC₁₋₁₀alkyl.

The term “alkoxy” or “alkyloxy” as used herein refers to a group havingthe formula —OR^(d) wherein R^(d) is alkyl. For instance, the term“C₁₋₂₀alkoxy” or “C₁₋₂₀alkyloxy” refers to a group having the formula—OR^(d) wherein R^(d) is C₁₋₂₀alkyl For instance,the “C₁₋₆alkoxy” or“C₁₋₆alkyloxy” refers to a group having the formula —OR^(d) whereinR^(d) is C₁₋₆alkyl. Non-limiting examples of suitable alkoxy includemethoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy,tert-butoxy, pentyloxy and hexyloxy.

The terms “heterocyclyl” or “heterocyclo” as used herein by itself or aspart of another substituent refer to non-aromatic, fully saturated orpartially unsaturated cyclic groups (for example, 3 to 13 membermonocyclic, 7 to 17 member bicyclic, or 10 to 20 member tricyclic ringsystems, or containing a total of 3 to 10 ring atoms) which have atleast one heteroatom in at least one carbon atom-containing ring. Eachring of the heterocyclic group containing a heteroatom may have 1, 2, 3or 4 heteroatoms selected from nitrogen atoms, oxygen atoms and/orsulfur atoms, where the nitrogen and sulfur heteroatoms may optionallybe oxidized and the nitrogen heteroatoms may optionally be quaternised.The heterocyclic group may be attached at any heteroatom or carbon atomof the ring or ring system, where valence allows. The rings ofmulti-ring heterocycles may be fused, bridged and/or joined through oneor more spiro atoms. An optionally substituted heterocyclic refers to aheterocyclic having optionally one or more substituents (for example 1to 4 substituents, or for example 1, 2, 3 or 4), selected from thosedefined above for substituted aryl.

Exemplary heterocyclic groups include piperidinyl, azetidinyl,imidazolinyl, imidazolidinyl, isoxazolinyl, oxazolidinyl,isoxazolidinyl, thiazolidinyl, isothiazolidinyl, piperidyl,succinimidyl, 3H-indolyl, isoindolinyl, chromenyl, isochromanyl,xanthenyl, 2H-pyrrolyl, 1-pyrrolinyl, 2-pyrrolinyl, 3-pyrrolinyl,pyrrolidinyl, 4H-quinolizinyl, 4aH-carbazolyl, 2-oxopiperazinyl,piperazinyl, homopiperazinyl, 2-pyrazolinyl, 3-pyrazolinyl, pyranyl,dihydro-2H-pyranyl, 4H-pyranyl, 3,4-dihydro-2H-pyranyl, phthalazinyl,oxetanyl, thietanyl, 3-dioxolanyl, 1,4-dioxanyl, 2,5-dioximidazolidinyl,2,2,4-piperidonyl, 2-oxopiperidinyl, 2-oxopyrrolodinyl, 2-oxoazepinyl,indolinyl, tetrahydropyranyl, tetrahydrofuranyl, tetrehydrothienyl,tetrahydroquinolinyl, tetrahydroisoquinolinyl, thiomorpholinyl,thiomorpholinyl sulfoxide, thiomorpholinyl sulfone, 1,3-dioxolanyl,1,4-oxathianyl, 1,4-dithianyl, 1,3,5-trioxanyl, 6H-1,2,5-thiadiazinyl,2H-1,5,2-dithiazinyl, 2H-oxocinyl, 1H-pyrrolizinyl,tetrahydro-1,1-dioxothienyl, N- formylpiperazinyl, and morpholinyl.

The term “oxo” as used herein refers to the group ═O.

The term “halo” as used herein refers to a halogen group, for example,fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).

The term “alkylcarbonyloxy” by itself or as part of another substituentrefers to a —O—C(═O)R^(e) wherein R^(e) is as defined above for alkyl.

The term “alkenylcarbonyloxy” by itself or as part of anothersubstituent refers to a —O—C(═O)R^(f) wherein R^(f) is as defined abovefor alkenyl.

The term “alkoxycarbonyl” by itself or as part of another substituentrefers to a carboxy group linked to an alkyl i.e. to form —C(═O)OR^(e),wherein R^(e) is as defined above for alkyl.

The term “hydroxylcarbonyl” by itself or as part of another substituentrefers to a hydroxyl group linked to a carbonyl group i.e. to formHO—(C═O)—.

The term “aryloxy” by itself or as part of another substituent refers toa group having the formula —OR^(a) wherein R^(a) is aryl as definedherein. For instance, C₆₋₃₀aryloxy refers to a group having the formula—OR^(a) wherein R^(a) is C₆₋₃₀aryl as defined herein. For instance,C₆₋₁₂aryloxy refers to a group having the formula —OR^(a) wherein R^(a)is C₆₋₁₂aryl as defined herein. Non-limiting examples of suitableC₆₋₁₂aryl include phenoxy, 2-naphthoxy and 1-naphthoxy.

In an embodiment, the compound has formula (I) and R¹ is a groupselected from C₁-C₁₅alkyl; C₃₋₈cycloalkyl; C₂-C₁₅alkenyl; C₂-C₁₅alkynyl;C₂-C₈alkenylcarbonyloxyC₁-C₈alkyl; heterocycylC₁-C₄alkyl;hydroxylcarbonylC₁-C₅₀alkyl;C₆-C8arylC₁-C₄alkyloxycarbonylaminoC₁-C₈alkyl; aminoC₁-C₈alkyl;haloC₁-C₈alkylcarbonyloxyC₁-C ₈alkyl; hydroxyC₁-C₈alkyl; heterocycyl;C₆-C₈arylC₁-C₄alkyl; each group being optionally substituted by one ormore substituents selected from C₁-C₆alkyl, hydroxyl, oxo, or whereinsaid at least one carbon atom in the heterocyclyl is optionallysubstituted by one or more oxo group, or wherein at least one nitrogenatom in the heterocyclyl is optionally substituted by an oxyl freeradical;

or the compound is a polymer selected from the group comprisingpolyolefin, polyester, polycarbonate, polypropylene, polyethylene, poly(L) lactic acid, poly (D) lactic acid, poly (D,L) lactic acid,polybutylene succinate, polycaprolactone, polytrimethylene carbonate,polyalkylenecarbonate, polysiloxane, polyether, polystyrene,polyisoprene, polyamine, polyamide, polyvinyl alcohol, polyurethane,polyacrylate and polyaminoacid, and containing n OH and/or NH₂ group,where n is an integer greater than or equal to 1.

In an embodiment, the compound has formula (I) and R¹ is a groupselected from C₁-C₁₀alkyl; C₃₋₈cycloalkyl; C₂-C₁₀alkenyl; C₂C₁₀alkynyl;C₂-C₄alkenylcarbonyloxyC₁-C₆alkyl; heterocycylC₁-C₄alkyl;hydroxylcarbonylC₁-C₂₅alkyl; C₆-C₇arylC₁-C₃alkyloxycarbonylamino C₁-C₆alkyl; aminoC₁-C₆alkyl; haloC₁-C₆alkylcarbonyloxyC₁-C₆alkyl;hydroxyC₁-C₆alkyl; heterocycyl; C₆-C₈arylC₁-C₂alkyl;; each group beingoptionally substituted by one or more substituents selected fromC₁-C₄alkyl, hydroxyl, oxo, or wherein said at least one carbon atom inthe heterocyclyl is optionally substituted by one or more oxo group, orwherein at least one nitrogen atom in the heterocycly is optionallysubstituted by an oxyl free radical,

or

the compound is a polymer selected from the group comprising polyolefin,polyester, polycarbonate, polypropylene, polyethylene, poly (L) lacticacid, poly (D) lactic acid, poly (D,L) lactic acid, polybutylenesuccinate, polycaprolactone, polytrimethylene carbonate,polyalkylenecarbonate, polysiloxane, polyether, polystyrene,polyisoprene, polyamine, polyamide, polyvinyl alcohol, polyurethane,polyacrylate and polyaminoacid, and containing n OH and/or NH₂ group,where n is an integer greater than or equal to 1.

The process employs ring-opening oligomerisation of lactide in thepresence of a transfer agent that is the compound of formula (I).Oligomerisation is performed in the presence of a catalyst, which ispreferably a metal catalyst. Oligomerisation can performed using atechnique of melt polymerization (bulk) or in solvent. Oligomerisationcan be performed in one pot reactor.

Oligomerisation can be performed at a temperature of 70° C.-190° C.Preferably, the reaction is performed at a temperature of greater than105° C., 106° C., 107° C., 108° C., 109° C., or 110° C. The temperatureis preferably that of the reaction itself. According to an embodiment,the oligomerisation can be performed at a temperature of at least 110°C. when the catalyst has general formula III. According to anembodiment, the oligomerisation can be performed at a temperature of atleast 140° C. when the catalyst has general formula M(Y¹,Y², . . .Y^(p))_(q). According to an embodiment, without solvent, oligomerisationcan be performed at a temperature of 110° C.-190° C. in bulk. Accordingto an embodiment, with solvent, oligomerisation can be performed at atemperature of 90° C.-120° C. According to an embodiment, withoutsolvent, oligomerisation can be performed at a temperature of 140-190°C. in bulk when the catalyst has general formula M(Y¹,Y², . . .Y^(p))_(q). According to an embodiment, with solvent, oligomerisationcan be performed at a temperature of 90° C.-120° C. when the catalysthas general formula M(Y¹,Y², . . . Y^(p))_(q). According to anembodiment, without solvent, oligomerisation can be performed at atemperature of 110-190° C. in bulk when the catalyst has general formula(III). According to an embodiment, with solvent, oligomerisation can beperformed at a temperature of −90-120° C. when the catalyst has generalformula (III).

In an embodiment, R¹ is a group selected from C₁-C₂₀alkyl;C₃₋₈cycloalkyl; C₂-C₂₀alkenyl; C₂-C₂₀alkynyl;C₂-C₁₀alkenylcarbonyloxyC₁-C₁₀alkyl; heterocycyl C₁-C₆ alkyl; hydroxylcarbonyl C₁-C₁₀₀alkyl; C₆-C₁₀ aryl C₁-C₆ alkyl oxy carbonyl aminoC₁C₁₀alkyl; amino C₁-C₁₀alkyl; halo C₁-C₁₀alkylcarbonyloxyC₁-C₁₀alkyl;hydroxyC₁-C₁₀alkyl; heterocycyl; C₆-C ₁₀arylC₁-C6alkyl; each group beingoptionally substituted by one or more substituents selected fromC₁-C₆alkyl, hydroxyl, oxo, or wherein said at least one carbon atom inthe heterocyclyl is optionally substituted by one or more oxo group, orwherein at least one nitrogen atom in the heterocycly is optionallysubstituted by an oxyl free radical and the reaction is performedwithout solvent. The temperature of the reaction can be 140-190° C. inbulk conditions; the catalyst preferably has a general formula M(Y¹,Y²,. . . Y^(p))_(q). The temperature of the reaction can be 110-190° C. inbulk conditions; the catalyst preferably has general formula (III).

In an embodiment, the compound is a polymer selected from the groupcomprising polyolefin, polyester, polycarbonate, polypropylene,polyethylene, poly (L) lactic acid, poly (D) lactic acid, poly (D,L)lactic acid, polybutylene succinate, polycaprolactone, polytrimethylenecarbonate, polyalkylenecarbonate, polysiloxane, polyether, polystyrene,polyisoprene, polyamine, polyamide, polyvinyl alcohol, polyurethane,polyacrylate and polyaminoacid, and containing n OH and/or NH₂ group,where n is an integer greater than or equal to 1, and the reaction canbe performed with or without solvent. The temperature of the reactioncan be 90-120° C. when solvent is used; preferably the catalyst hasgeneral formula M(Y¹,Y², . . . Y^(p))_(q). The temperature of thereaction can be 90-120° C. when solvent is used; preferably the catalysthas general formula (III).

The temperature of the reaction can be at least 140° C., preferably140-190° C. when no solvent is used; the catalyst preferably has generalformula M(Y¹,Y², . . . Y^(p))_(q). The temperature of the reaction canbe at least 90° C., preferably 90-120° C. when solvent is used; thecatalyst preferably has general formula (III).

The mole ratio of lactide to the compound.n, may be equal to or below70, for example, 7 to 60, for example, 7 to 40 i.e. the lactide is inexcess. Compound.n refers to the number of moles of compound multipliedby the total number (n) of OH and/or NH₂ groups in the compound. Theletter n refers to the total number of OH and/or NH₂ groups present inthe compound. More specifically, n is the number OH groups when thecompound contains OH groups but not NH₂ groups, or n is the number NH₂groups when the compound contains NH₂ groups but not OH groups, or n isthe number OH groups and NH₂ groups combined when the compound containsmix of both OH groups and NH₂ groups. The OH and NH₂ groups are part ofthe compound by covalent attachment.

Suitable solvents include toluene, xylene, THF, C₄-C₂₀ alkane optionallybranched (heptane hexane, isobutane), ethyl acetate DMF or mixturethereof.

As a result, the instant invention can provide a simplified process(e.g. one-pot-one-step), which reduces manufacturing costs. Solvent isoptional. Oligomerisation can proceed under normal pressure. Both batchand continuous processes (plug-flow) can be considered. Advantageouslyhigh conversion in short reaction time can be obtained. The compound canalso be used to introduce additional functionalities into the lacticacid oligomers. The products can be well defined. Narrow polydispersitycould be observed in terms of final molecular weight. Low amount ofby-products were observed. It is a versatile process, giving access tobroad range of products in the same production unit. The same productionunit for very high molecular weight PLA can be readily used to makeoligomers.

Defining the mole ratio leads to a lactic acid chain formed by reactionof 70 or less lactides; hence the upper limit of the molecular weight ofthe oligomer is determined by this ratio. Typically a lactic acidoligomer prepared according to the process will have a (number averagemolecular weight (Mn) minus the molecular weight of the compound)/n ofup to 10 100 g/mol,

${\frac{{{Mn}\left( {{lactic}\mspace{14mu} {acid}\mspace{14mu} {oligomer}} \right)} - {{Mw}({compound})}}{n} \leq {10\; 100\; g\text{/}{mol}}},$

wherein Mn(lactic oligomer) is measured by size exclusionchromatography, and wherein n is number of OH and NH₂ groups present inthe compound. Typically between 900 and 8 900 g/mol. It will beappreciated that the compound of the calculation is the substanceincorporated into the lactic acid oligomer.

One factor that governs the number average molecular weight is the ratioof lactide to compound. The use of a quenching agent that stopsoligomerisation may also be used to control the number average molecularweight.

Number average molecular weight may be determined using any technique,for instance, using size exclusion chromatography (SEC). Typically,elution curves are calibrated with polystyrene standards.

According to one technique, SEC is performed using a VISCOTEK GPC maxapparatus, using tetrahydrofuran (THF) as solvent at 25° C., using aPLgel 5 μm MIXED-C 200×75 mm column (Aligent), at a flow rate of 1ml/minwith a sample volume of 150 μl, a refractive index detector, andanalysis using Waters Empower software. Elution curves are calibratedwith polystyrene standards.

Suitable the lactide to be used in the reaction can be a racemate, or anisomer such as L,L-lactide, D,D-lactide, and D,L-lactide. L,L-lactide ispreferably used. The lactide may be produced by any known process. Asuitable process for preparing L,L-lactide is described, for example, inWO 2004/041889 which is incorporated herein by reference.

According to the invention, R¹ can be C₁-C₂₀alkyl. For example R¹ isC₁-C₁₈alkyl, for example R¹ is C₁-C₁₄alkyl, for example R¹ isC₁-C₁₂alkyl, for example R¹ is C₁-C₁₀alkyl, for example, R¹ is C¹-C³alkyl or C⁵-C²⁰alkyl. R¹ can be selected from ethyl, propyl, prop-2-ylor octyl. When R¹ is octyl, n is preferably 1. When R¹ is propyl, n ispreferably 1 or 3. According to the invention, R¹ can be hydroxyl C₁-C₃or hydroxyl C₅-C₁₀ alkyl, and n is 2. When R¹ is ethyl, n is preferably2. X¹ is preferably hydroxyl.

According to the invention, R¹ can be C₃₋₈cycloalkyl, for instance, R¹can be C₃₋₈cycloalkyl, for instance, R¹ can be C₃₋₆cycloalkyl, forinstance, R¹ can be C₃₋₅cycloalkyl. R¹ can be selected from cyclopropyl,cyclobutyl, cyclopentyl, or cyclohexyl.

According to the invention, R¹ can be C₂-C₂₀ alkenyl, for instance, R¹can be C₂-C₁₈ alkenyl, for instance, R¹ can be C₂-C₁₆ alkenyl, forinstance, R¹ can be C₂-C₁₄alkenyl, for instance, R¹ can be C₂-C₁₂alkenyl, for instance, R¹ can be C₂-C₁₀ alkenyl, for instance, R¹ can beC₂-C₈ alkenyl, for instance, R¹ can be C₂-C₆ alkenyl, for instance, R¹can be C₂-C₄alkenyl. R¹ can be selected from ethenyl, propenyl,buten-1-yl, buten-2-yl, or another longer chain alkenyl.

According to the invention, R¹ can beC₂-C₁₀alkenylcarbonyloxyC₁-C₁₀alkyl. For example R¹ can beC₂-C₆alkenylcarbonyloxyC₁-C₆alkyl, for example R¹ can beC₂-C₄alkenylcarbonyloxyC₁-C₄alkyl. R¹ can be selected fromprop-2-enecarbonyloxyethyl, prop-2-enecarbonyloxypropyl,prop-2-enecarbonyloxymethyl, ethylenecarbonyloxymethyl,ethylenecarbonyloxyethyl, ethylenecarbonyloxypropyl. n is preferably 1.X¹ is preferably hydroxyl. In a particular embodiment, the oligomer soformed can be used for the preparation of modified polystyrene. This isparticularly applicable when R¹ is C₂-C ₁₀alkenylcarbonyloxyC₁-C₁₀alkyl,such as prop-2-enecarbonyloxyethyl.

According to the invention, R¹ can be heterocyclyl, for example, R¹ canbe heterocyclyl optionally substituted by one or more substituentsselected from C₁-C₆alkyl, hydroxyl, or oxo. The heterocyclyl may be a 3,4, 5, 6, 7, 9 or 10 member monocyclic ring system, containing 1, 2 or 3heteroatoms each independently selected from O or N. According to theinvention R¹ can be an epoxymethyl, or dioxolone-2-oxo-methyl. n ispreferably 1. X¹ is preferably hydroxyl.

According to the invention, R¹ can be hydroxylcarbonyl C₁-C₁₀₀alkyl, forexample, R¹ can be hydroxylcarbonylC₁-C₅₀alkyl, R¹ can behydroxylcarbonylC₁-C₂₅alkyl, R¹ can be hydroxylcarbonylC₁-C₁₅ alkyl, R¹can be hydroxylcarbonylC₁-C₁₀alkyl, R¹ can behydroxylcarbonylC₁-C₆alkyl, or R¹ can be hydroxyl carbonylC₁-C₄alkyl. nis preferably 1. X¹ is preferably hydroxyl.

According to the invention, R¹ can beC₆-C₁₀arylC₁-C₆alkyloxycarbonylaminoC₁-C₁₀alkyl, for example, R¹ can beC₆-C₈arylC₁-C₄alkyloxycarbonylaminoC₁-C₆ alkyl, for example R¹ can beC₆-C₇arylC₁-C₄alkyloxycarbonylaminoC₁-C₄ alkyl, for example R¹ can bephenylmethoxycarbonylaminopropyl. n is preferably 1. X¹ is preferablyhydroxyl.

According to one embodiment of the invention, the oligomer so formed,when R¹ is C₆-C₁₀arylC₁-C₆alkyloxycarbonylaminoC₁-C₁₀alkyl, can befurther treated to remove the C₆-C₁₀arylC₁-C₆alkyloxycarbonyl group,thereby leaving the amino C₁-C₁₀ alkyl part of the compound attached tothe oligomeric lactic acid. Treatment is preferably with a suitable basesuch as piperidine, optionally in the presence of a suitable solventsuch as in dichloromethane.

According to the invention, R¹ can behaloC₁-C₁₀alkylcarbonyloxyC₁-C₁₀alkyl, For example, R¹ can behaloC₁-C₈alkylcarbonyloxyC₁-C₁₀alkyl, for example R¹ can behaloC₁-C₆alkylcarbonyloxyC₁-C₁₀alkyl, for example R¹ can behaloC₁-C₆alkylcarbonyloxyC₁-C₁₀alkyl, for example R¹ can behaloC₁-C₄alkylcarbonyloxyC₁-C₁₀alkyl, for example R¹ can behaloC₁-C₈alkylcarbonyloxyC₁-C₈alkyl, for example R¹ can behaloC₁-C₈alkylcarbonyl oxyC₁-C₆alkyl, for example R¹ can behaloC₁-C₈alkylcarbonyloxyC₁-C₄alkyl, for example R¹ can bebromideisoethylcarbonyloxyethyl. n is preferably 1. X¹ is preferablyhydroxyl.

According to the invention, R¹ can be a heterocycyl, for example, R¹ canbe a heterocycyl monocyclic 4 to 6 member ring system, having 1, 2,or 3heteroatoms. The heteroatom may be O or N. According to the invention,R¹ can be 6-membered ring where the heteroatom is N. The heterocycyl canbe substituted by one or more substituents each independently selectedfrom C₁-C₆alkyl, oxyl free radical, oxo. R¹ can be 2,2,6,6tetramethylpiperidinyl-1-oxyl, preferably having the formula (II):wherein the asterisk indicates the point of attachment of X¹. X¹ ispreferably hydroxyl. n is preferably 1, the compound is 2,2,6,6tetramethyl

In a particular embodiment, the oligomer so formed when R¹ isheterocycyl can be used to prepare modified polystyrene. This isparticularly applicable when R¹ is heterocycyl is substituted by an oxylfree radical, more particularly when is R¹ is 2,2,6,6 tetramethylpiperidine-1-oxyl.

According to the invention, R¹ can be C₆-C₁₀aryl C₁-C₆alkyl, forexample, R¹ can be C₆-C₈arylC₁-C₄alkyl, for example, R¹ can beC₆-C₈arylC₁-C₂alkyl for example, R¹ can be benzyl. X¹ is preferablyamine (e.g. NH₂). n is preferably 1.

According to the invention, the compound can be a polymer, for example,the compound can be a polyolefin, the compound can be a polyester, thecompound can be a polycarbonate, the compound can be polypropylene, thecompound can be polyethylene, the compound can be poly (L) lactic acid,the compound can be poly (D) lactic acid, the compound can be poly (D,L)lactic acid, the compound can be polybutylene succinate, the compoundcan be polycaprolactone, the compound can be polytrimethylene carbonate,the compound can be polyalkylenecarbonate, the compound can bepolysiloxane, the compound can be polyether, the compound can bepolystyrene, the compound can be polyisoprene, the compound can bepolyamine, the compound can be polyamide, the compound can be polyvinylalcohol, the compound can be polyurethane, the compound can bepolyacrylate or the compound can be polyaminoacid; in each case thepolymer contains n OH and/or NH₂ group(s), where n is an integer greaterthan or equal to 1.

When the polymer contains n OH and/or NH₂ group(s), where n is aninteger greater than or equal to 1, it means that at least one OH and/orat least one NH₂ group(s) may be present in the native polymer, or thatthe native polymer is modified with an hydroxyl (OH) or amine (e.g. NH₂)group or both, for instance, by end-capping at one or both ends. It willbe appreciated that n will be an integer n is an integer greater than orequal to 2 when the polymer contains at least one OH and at least oneNH₂ group. In an example, native polyvinyl alcohol polymer or nativepolyacrylate polymer contains OH groups; these polymers may optionallybe end capped with OH or NH₂. According to a particular instance, thecompound may be polypropylene end-capped with an hydroxyl. The hydroxyl-or amine-capped polymer may be formed from a polymer end-capped with avinyl group. For example, the compound may be formed from polypropyleneend-capped with a vinyl group.

When more than one compound is employed, it is meant that the compoundsare different. One or more compounds includes mixtures of differentpolymers (i.e. polymer blends). One or more compounds includes mixturesof different compounds having formula (I). One or more compoundsincludes mixtures of different compounds having formula (I), or mixturesof different polymers (i.e. polymer blends). According to one aspect,one or more compounds refers to a mixture of one or more compoundshaving formula (I) and one or more polymers (i.e. polymer blends). Theremay be 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more different compoundsemployed in the method.

When more than one compound is present in the method and each compoundhas a different number n, for instance when the method is performedusing a blend of different polymers, the reactions conditions are setsuch that the mole ratio of lactide to (compound.n) is equal to or below70 for each compound. This allows each OH or NH₂ group of each compoundto be present where lactide is in mole excess of each group by a factorof 70 or less. Eq. 1 sets out the mole ratio lactide:(compound.n) formu_(k) moles of lactide, m_(Cmp1) moles of compound 1, in which amolecule of compound 1 contains n_(Cmp1) number of OH and/or NH₂ groups.

$\begin{matrix}{\frac{m_{LA}}{n_{{Cmp}\; 1}m_{{Cmp}\; 1}} \leq 70} & \left\lbrack {{Eq}.\mspace{14mu} 1} \right\rbrack\end{matrix}$

Where there is a blend of different compounds (e.g. a polymer blend),Eq.2 sets out the mole ratio lactide:(compound.n), for m_(LA) moles oflactide and a blend of different compounds (Cmp1 to Cmp 5) containingm_(mp1) moles of compound 1, in which a molecule of compound 1 containsn_(Cmp1) number of OH and/or NH₂ groups, m_(Cmp2) moles of compound 2,in which a molecule of compound 2 contains n_(Cmp2) number of OH and/orNH₂ groups . . . m_(Cmp5) moles of compound 5, in which a molecule ofcompound 5 contains n_(Cmp5) number of OH and/or NH₂ groups.

$\begin{matrix}{\frac{m_{LA}}{\begin{matrix}{\left\lbrack {n_{{Cmp}\; 1}m_{{Cmp}\; 1}} \right\rbrack + \left\lbrack {n_{{Cmp}\; 2}m_{{Cmp}\; 2}} \right\rbrack + \ldots +} \\\left\lbrack {n_{{Cmp}\; 5}m_{{Cmp}\; 5}} \right\rbrack\end{matrix}} \leq 70} & \left\lbrack {{Eq}.\mspace{14mu} 2} \right\rbrack\end{matrix}$

The value of n is at least one, for example, a value in the range 1-10,1-20, 1-30 or 1 to 500. Preferably n is 1, 2, 3, 4, 5, 6, 7, 8, or 10.When n is greater than 1 for a compound, the formation of newarchitectures is possible via the oligomerisation of the presentprocess. When n=2, propeller (2-bladed) copolymers are formed having anon-lactic acid core, and oligomeric lactic acid blades. When n=3, star(3-bladed) copolymers are formed having a non-lactic acid core, andoligomeric lactic acid blades. Accordingly, the oligomer branches with awell defined length and end groups originating from the compound. Thisis particular suitable when the compound is a polymer selected from thegroup comprising polypropylene, polyethylene, poly (L) lactic acid, poly(D) lactic acid, poly (D,L) lactic acid, polysiloxane, polybutylenesuccinate, polytrimethylene carbonate, polycaprolactone, polyester,polyether, polyolefin, polystyrene, polyisoprene, polycarbonate,polyalkylenecarbonate, polyamine, polyamide, polyvinyl alcohol,polyurethane, polyacrylate and polyaminoacid, and containing n OH and/orNH₂ group(s), where n is an integer greater than or equal to 1.

The terminal groups (hydroxyl or amine) of each lactic acid oligomericchain resulting from the process of the invention are available forfurther reactions. In other words, telechelic oligomers are formed bythe process of the invention, in particular when n>1 (e.g. n=2); thesecan act as macroinitiators for the further preparation of multiblockcopolymers, having a non-lactic acid core. This is particularly suitablewhen the compound is a polymer. The polymer preferably containshydroxyl, or X¹ is preferably hydroxyl. Accordingly, a furtherembodiment of the invention is a use of an oligomer prepared accordingto the present method for the further preparation of multiblockcopolymers

Other compounds that give some specific microstructure in ROP of lactidecould be considered such as branching agents and the like.

The catalytic system used for producing the lactic oligomers may be anysuitable catalytic system. Suitable catalysts according to the inventionare organometallic catalysts. Examples of organometallic catalystsfollow. Suitable catalysts according to the invention can be catalyst ofgeneral formula M(Y¹,Y², . . . Y^(p))_(q), in which M is a metalselected from the group comprising the elements of columns 3 to 12 ofthe periodic table of the elements, as well as the elements Al, Ga, In,Tl, Ge, Sn, Pb, Sb, Ca, Mg and Bi; whereas Yl, Y², . . . Y^(p) are eachsubstituents selected from the group comprising C₁₋₂₀alkyl, C₆₋₃₀aryl,C₁₋₂₀alkoxy , C₆₋₃₀aryloxy, and other oxide, carboxylate, and halidegroups as well as elements of group 15 and/or 16 of the periodic table;p and q are integers between 1 and 6. As examples of suitable catalysts,we may notably mention the catalysts of Sn, Ti, Zr, Zn, and Bi;preferably an alkoxide or a carbon/late and more preferably Sn(Oct)₂,Ti(OiPr)₄, Ti(2-ethylhexanoate)₄, Ti(2-ethylhexyloxide)₄, Zr(OiPr)₄,Bi(neodecanoate)₃ or Zn(lactate)₂.

Other suitable catalysts can be catalyst of general formula (Ill):

wherein

R² and R³ are each independently C₁₋₁₀alkyl,

R⁴, R⁵ and R⁶ are each independently C₁₋₁₀alkyl, or

R⁴ and R⁵ are covalently bound to each other and are each a methyleneand

R⁶ is C₁₋₁₀alkyl,

X² is selected from C₁₋₁₀alkyl, —OR⁷, or —N(SiR⁸ ₃)₂, R⁷ is C₁₋₁₀alkyl,and R⁸ is C₁₋₆alkyl.

R² and R³ are each independently C₁₋₁₀alkyl; preferably, R² and R³ areeach independently C₁₋₆alkyl; preferably, R² and R³ are eachindependently C₁₋₄alkyl; for example, R² and R³ can be eachindependently selected from the group consisting of methyl, ethyl,n-propyl, i-propyl, 2-methyl-ethyl, n-butyl, i-butyl and t-butyl;preferably, R² and R³ can be each independently selected from the groupconsisting of methyl, ethyl, i-propyl and t-butyl; for example R² and R³can be each independently selected from i-propyl or t-butyl; preferably,R² and R³ are t-butyl,

R⁴, R⁵ and R⁶ are each independently C₁₋₁₀alkyl, preferably, R⁴, R⁵ andR⁶ are each independently C₁₋₆alkyl, preferably R⁴, R⁵ and R⁶ are eachindependently C₁₋₄alkyl, for example, R⁴, R⁵ and R⁶ can be eachindependently selected from the group consisting of methyl, ethyl,n-propyl, i-propyl, 2-methyl-ethyl, n-butyl, i-butyl and t-butyl; forexample, R⁴, R⁵ and R⁶ can be each independently selected from the groupconsisting of methyl, ethyl, i-propyl and t-butyl; for example, R⁴, R⁵and R⁶ are each independently selected from methyl or ethyl; preferably,R⁴, R⁵ and R⁶ are each independently methyl, or R⁴ and R⁵ are covalentlybound to each other and are each a methylene and R⁶ is C₁₋₁₀alkyl;preferably R⁶ is C₁₋₆alkyl; preferably, R⁶ is C₁₋₄ aalkyl; for exampleR⁶ can be selected from the group consisting of methyl, ethyl, n-propyl,i-propyl, 2-methyl-ethyl, n-butyl, i-butyl and t-butyl; for example R⁶can be selected from the group consisting of methyl, ethyl, i-propyl andt-butyl; for example R⁶ can be selected from methyl or ethyl; forexample R⁶ can be methyl;

X² is selected from C₁₋₁₀alkyl, —OR⁷, or —N(SiR⁸ ₃)₂, R⁷ is C₁₋₁₀alkyl,and R⁸ is C₁₋₆alkyl; preferably, X² is selected from C₁₋₆alkyl, —OR⁷, or—N(SiR⁸ ₃)₂, R⁷ is C₁₋₆alkyl, and R⁸ is C₁₋₆alkyl; preferably, X² isselected from C₁₋₄alkyl, —OR⁷, or —N(SiR⁸ ₃)₂, R⁷ is C₁₋₄alkyl, and R⁸is C₁₋₄alkyl; for example X² can be selected from the group consistingof methyl, ethyl, n-propyl, i-propyl, 2-methyl-ethyl, n-butyl, i-butyland t-butyl, or —OR⁷, or —N(SiR⁸ ₃)₂, R⁷ can be selected from the groupconsisting of methyl, ethyl, n-propyl, i-propyl, 2-methyl-ethyl,n-butyl, i-butyl and t-butyl, and R⁵ can be selected from the groupconsisting of methyl, ethyl, n-propyl, i-propyl, 2-methyl-ethyl,n-butyl, i-butyl and t-butyl; preferably, X² can be selected from thegroup consisting of methyl, ethyl, i-propyl and n-butyl, or —OR⁷, R⁷ canbe selected from the group consisting of methyl, ethyl, i-propyl andt-butyl; preferably, X² can be selected from —OR⁷, R⁷ can be selectedfrom the group consisting of methyl, ethyl, i-propyl and t-butyl;preferably, X² can be —OR⁷, and R⁷ is ethyl.

In an embodiment, R² and R³ are each independently C₁₋₆alkyl.Preferably, R² and R³ can be each independently selected from the groupconsisting of methyl, ethyl, i-propyl and t-butyl; for example R² and R³can be each independently selected from i-propyl or t-butyl; preferably,R² and R³ are t-butyl.

In an embodiment, R⁴, R⁵ and R⁶ are each independently C₁₋₆alkyl. Forexample, R⁴, R⁵ and R⁶ can be each independently selected from the groupconsisting of methyl, ethyl, i-propyl and t-butyl; preferably, R⁴, R⁵and R⁶ can be each independently selected from methyl or ethyl; morepreferably, R⁴, R⁵ and R⁶ can be methyl.

For example, the process can be performed with a catalyst of Formula(III) wherein, R² and R³ are each independently C₁₋₆alkyl; R⁴, R⁵ and R⁶are each independently C₁₋₆alkyl; and X² is selected from C₁₋₆alkyl,—OR⁷, or —N(SiR⁸ ₃)₂, R⁷ is C₁₋₆alkyl, and R⁵ is C₁₋₆alkyl.

For example, the process can be performed with a catalyst of Formula(III) wherein, R² and R³ are each independently C₁₋₆alkyl; R⁴ and R⁵ arecovalently bound to each other and are each a methylene and R⁶ isC₁₋₆alkyl; and X² is selected from C₁₋₆alkyl, —OR⁷, or —N(SiR⁸ ₃)₂, R⁷is C₁₋₆alkyl, and R⁸ is C₁₋₆alkyl.

For example, the oligomerisation of lactide into lactic acid oligomerscan be performed with a catalyst of Formula (III) wherein, R² and R³ areeach independently C₁₋₄alkyl; R⁴, R⁵ and R⁶ are each independentlyC₁₋₄alkyl, X² is selected from C₁₋₄alkyl, —OR⁷, or —N(SiR⁸ ₃)₂, R⁷ isC₁₋₄alkyl, and R⁸ is C₁₋₄alkyl.

For example, the oligomerisation of lactide into lactic acid oligomerscan be performed with a catalyst of Formula (III) wherein, R² and R³ areeach independently C₁₋₄alkyl; R⁴ and R⁵ are covalently bound to eachother and are each a methylene and R⁶ is C₁₋₄alkyl; and X² is selectedfrom C₁₋₄alkyl, —OR⁷, or —N(SiR⁸ ₃)₂, R⁷ is C₁₋₄alkyl, and R⁸ isC₁₋₄alkyl.

In a preferred embodiment, R² and R³ are each independently C₁₋₄alkyl,preferably t-butyl or isopropyl; R⁴, R⁵ and R⁶ are each independentlyC₁₋₂alkyl, X² is —OR⁷, and R⁷ is C₁₋₂alkyl.

In a preferred embodiment, R² and R³ are each independently C₁₋₄alkyl,preferably t-butyl or isopropyl; R⁴ and R⁵ are covalently bound to eachother and are each a methylene and R⁶ is C₁₋₂alkyl; X² is —OR⁷, R⁷ isC₁₋₂alkyl.

In an embodiment, the catalyst is Formula (IIIa), (IIIb), (IIIc) or(IIId),

wherein R², R³, R⁴, R⁵, R⁶ and X² have the same meaning as that definedabove.

In an embodiment, said catalyst of Formula (III) is(2,4-di-tert-butyl-6-(((2-(dimethylamino)ethyl)(methyl)amino)methyl)phenoxy)(ethoxy)zinc,also referred to as “DDTBP-Zn (OEt)” represented by Formula (IV).

(2,4-di-tert-butyl-6-(((2-(dimethylamino)ethyl)(methyl)amino) methyl)phenoxy)(ethoxy)zinc can be prepared as described in Williams et al. (J.Am. Chem. Soc., 2003, 125, 11350-59) hereby incorporated by reference.

The polymerization of lactide is performed in the presence of catalyst.The catalyst may be used in any amount where the lactide is in excess tocatalyst. For instance, the mole ratio of lactide to catalyst may beequal to or below 200 000, 100 000, 80 000, 60 000, 40 000, 20 000, 10000, 5 000, 3000, between 200 and 3 000, between 200 and 2800, orbetween 200 and 2 500.

Typically, the process of the invention is performed in a closedreaction vessel under an inert gas (e.g. nitrogen, helium) atmosphere.Preferably it is performed under melt conditions, in the absence ofadditional solvent. Preferably, the process is performed by contactingthe lactide with the catalyst and compound in a reactor preferablyequipped with an agitator for high viscosity or extrusion in a extruder(or horizontal reactor) in single, double or multiple screws in an inertatmosphere in the presence of argon or nitrogen. However, it can alsotake place under ambient. The temperature is regulated, for example, byimmersion of the vessel or reactor in an oil bath. The reaction may beterminated.

The oligomerisation reaction may optionally be stopped using any knowntermination technique. Typically, it is quenched using an acid chloride.The acid chloride preferably has the formula Cl—CO—R⁹, where R⁹ isselected from the group consisting of: alkynyl, aminoalkyl, alkyl, R¹.Most preferably, R⁹ is pent-1-ylnyl or aminoethyl. Alternatively, theoligomerisation reaction may be quenched by opening the reaction vessel,whereby atmospheric oxygen deactivates the catalyst.

The invention also relates to an oligomer prepared according to themethod of the invention. The product may have a (number averagemolecular weight (Mn) minus the molecular weight of the compound)/nequal to or less than 10 100 g/mol, typically 900 to 8 900 g/mol. Itwill be appreciated that the compound is the compound incorporated intothe lactic acid oligomer. When there is a mixture of compounds (e.g.polymer blend) a blend of oligomers results. For each compound of thepolymer blend the resulting product has a (Mn minus the molecular weightof the compound)/n equal to or less than 10 100 g/mol, typically 900 to8 900 g/mol.

EXAMPLES

1. Alcohol as Transfer Agent

Oligomeric L-lactic acids were synthesized by the ring-openingpolymerization of L-Lactide with an Sn(Oct)₂ catalyst (Cat) in thepresence of various kinds of alcohol as transfer agents that arecompounds having formula (I). Three different alcohols were used inseparate experiments, namely 1-Octanol, isopropanol and HEMA(2-hydroxyethyl metacrylate). The oligomeric products resulting from thevarious transfer agents are illustrated in Scheme 1 below.

The ring opening polymerization of L-Lactide was performed in bulk. Thereactions were carried out at a temperature ranging between 150° C. and185° C. Products were analysed by SEC. SEC was performed using aVISCOTEK GPC max instrument, with tetrahydrofuran (THF) as solvent at25° C., using a PLgel 5 μm MIXED-C 200×75 mm column (Aligent), at a flowrate of 1ml/min with a sample volume of 150 μl, a refractive indexdetector, and analysis using Waters Empower software. Elution curveswere calibrated with polystyrene standards.

The results of the experiments are presented in Table 1 below.

TABLE 1 Polymerization of L-LA in bulk at 150 and 185° C. usingSn(Oct)₂/ROH catalyst system. Ratio Ratio T Time Conv M_(n theo)W_(n SEC) ^(a) W_(n SEC) ^(a) Example ROH LA/Sn LA/ROH (° C.) (min) (%)(g/mol) (PS) (PLA) M_(w)/M_(n) ^(b) 1 Octanol 2 186   36.4 150 30 93.5 5035   9 971 5 783 1.26 2 Octanol 2 154   35.9 185 30 95.1 5 046   10276  5 960 1.68 3 Octanol 784 7.8 150 30 82.2 1 058   2 530 1 465 1.21 4Octanol 773 7.7 185 30 92.3 1 157   4 208 2 332 1.45 5 Octanol 246 4.1150 60 67.4 398 1 610   933 1.23 6 Octanol 244 4.06 185 30 71.5 485 2110 1 223 1.23 7 ^(i)PrOH 2 039   33.9 150 30 93.4 4 630   8 853 5 1351.36 8 ^(i)PrOH 713 7.1 150 30 83.4 916 2 076 1 204 1.23 9 ^(i)PrOH 2393.9 150 60 62.4 417 1 708   992 — 10 HEMA 1 969   32.8 150 30 96.2 5042   8 473 4 914 1.26 11 HEMA 706 7.06 150 30 84.1 985 2 236 1 296 1.1912 HEMA 247 4.1 185 30 69 540 1 688   979 — ^(a) Number averagemolecular weight of the oligomers as determined by SEC in THF vs.polystyrene (PS) standards and corrected by 0.58. ^(b) Molecular weightdistributions calculated from SEC traces.

The end-group structure of the polylactides was analyzed by ¹H and ¹³CNMR, which allowed us to calculate more precisely the molecular weightsof the resulting polymers. Moreover, the GPC is a good analysis todetermine the PLLA molecular weights too. Characterization of the PLAoligomers by ¹H and ¹³C NMR analysis in CDCl₃ revealed, besides the mainpolymer chain typical resonances, clearly the presence of both ahydroxymethyl and an alkoxy ester chain-end.

2. Amine as Transfer Agent

Oligomeric L-lactic acids were synthesized by the ring-openingpolymerization of L-Lactide with an Sn(Oct)₂ catalyst in the presence ofan amine transfer agent, benzyl amine. The reaction scheme isillustrated in Scheme 2 below.

The ring opening polymerization of L-Lactide was performed in bulk for30 minutes. The reactions were carried out at a temperature rangingbetween 150° C. and 185° C. Products were analysed by SEC. SEC wasperformed using a VISCOTEK GPC max instrument, with tetrahydrofuran(THF) as solvent at 25° C., using a PLgel 5 μm MIXED-C 200×75 mm column(Aligent), at a flow rate of 1ml/min with a sample volume of 150 μI, arefractive index detector, and analysis using Waters Empower software.Elution curves were calibrated with polystyrene standards. The resultsof the experuments are presented in Table 2 below.

TABLE 2 Oligomerisation of L-lactide in bulk at 150° C. and 185° C.using Sn(Oct)₂ catalyst system and BnNH₂ transfer agent. T Time ConvW_(n) _(theo) W_(n) _(SEC) ^(a) W_(n) _(SEC) ^(a) Example RNH₂ LA/SnLA/RNH₂ (° C.) (min) (%) (g/mol) (PS) (PLA) M_(w)/M_(n) ^(b) 13 BnNH₂ 1879   31.3 150 30 89.9 4 161   8 337 4 835 1.17 14 BnNH₂ 2 120   35.3185 30 92.4 4 808   10 112  5 865 1.65 15 BnNH₂ 763 7.63 150 30 84.4 9452 135 1 238 1.18 16 BnNH₂ 781 7.8 185 15 74.5 980 2 140 1 240 1.24 17BnNH₂ 244 60 150 60 77.3 581 2 009 1 165 1.21 ^(a) Number averagemolecular weight of the oligomers as determined by SEC in THF vs.polystyrene (PS) standards and corrected by 0.58. ^(b) Molecular weightdistributions calculated from SEC traces.

3. Diol and Triol Transfer Agents

Oligomeric L-lactic acids were synthesized by the ring-openingpolymerization of L-Lactide with an Sn(Oct)₂ catalyst in the presence ofa diol or triol transfer agents. This resulted in linear telechelicdihydroxy HO-PLLA-OH, or 3-arms star trihydroxy R-(PLLA-OH)₃ polymers.The transfer agents used were diol (1,3-propanediol) or a triol(glycerol). The reaction scheme is illustrated in Scheme 3 below.

The ring opening polymerization of L-Lactide was performed in bulk for30 minutes. The reactions were carried out at a temperature rangingbetween 150° C. and 185° C. Products were analysed by SEC. SEC wasperformed using a VISCOTEK GPC max instrument, with tetrahydrofuran(THF) as solvent at 25° C., using a PLgel 5 μm MIXED-C 200×75 mm column(Aligent), at a flow rate of 1ml/min with a sample volume of 150 μl, arefractive index detector, and analysis using Waters Empower software.Elution curves were calibrated with polystyrene standards. The resultsof the experiments are presented in Table 3 below.

TABLE 3 Polymerization of L-LA in bulk at 150 and 185° C. using Sn(Oct)₂catalyst and a diol (PPD) ortriol (GLY) transfer agent. T Time ConvM_(n theo) M_(n) _(SEC) ^(a) M_(n) _(SEC) ^(a) Example R(OH)_(n) LA/SnLA/R(OH)_(n) ^(c) (° C.) (min) (%) (g/mol) (PS) (PLA) Mw/M_(n) ^(b) 18PPD 1 945   32.4 150 30 93.3 4 431 7 625 4 422 1.18 19 PPD 751 7.5 18530 64.1 887   2 290 1 328 1.27 20 GLY 2 013   33.6 150 30 89.8 4 430 8890 5 156 1.24 21 GLY 697 6.96 150 30 95.8 1 054 2 540 1 473 1.17 22 GLY712 7.12 185 30 92.4 1 039 2 765  1604 1.34 ^(a) Number averagemolecular weights of the oligomers as determined by SEC in THFvs.polystyrene (PS) standards and corrected by 0.58. ^(b) Molecularweight distributions calculated from SEC traces. ^(c)The ratio is notcorrected to account for n number of OH groups.

¹H and ¹³C NMR analyses of the PLA oligomers showed, besides the mainpolymer chain typical resonances, the presence of a unique polymerchain-end identified by the characteristic signals of a hydroxylend-group. For the HO-PLA-OH and HO-PLA-(OH)₂ issued from the diol andthe triol, the central organic moiety was also unambiguously identified.These polymers, thanks to their hydroxyl end group, can act asmacroinitiators for the preparation of multiblock copolymers.

4. Functional Polymer as Transfer Agent

Oligomeric L-lactic acids were synthesized by the ring-openingpolymerization of L-Lactide with an Sn(Oct)₂ catalyst in the presence ofa hydroxyl-end capped macro polymer. Hydroxy-end-capped polypropylene(PP) was used as macro-initiators and transfer agents to prepare, withhigh efficiency, a variety diblock and triblock copolymers. The reactionscheme is illustrated in 4 below.

The ring opening polymerization of L-Lactide was performed in toluene.The reaction was carried out at a temperature of 110° C. Products wereanalysed by SEC. SEC was performed using a VISCOTEK GPC max instrument,with tetrahydrofuran (THF) as solvent at 25° C., using a PLgel 5 μmMIXED-C 200×75 mm column (Aligent), at a flow rate of 1ml/min with asample volume of 150 μl, a refractive index detector, and analysis usingWaters Empower software. Elution curves were calibrated with polystyrenestandards. The results of the experiments are presented in Table 4below.

Hydroxy-end-capped polypropylene initiators (PP-OH) which are used inthe examples below (Table 4) are derived from the propylene. Propyleneis first polymerized with a metallocene catalyst as described in U.S.Pat. No. 6,376,418B1. The polymer is subsequently submitted to ahydroboration/oxidation reaction in conditions described by Gray et al.;Macromolecules 1998, 31, 3417-3423). Finally the vinyl terminatedpolymer chains are converted to —OH terminated ones.

TABLE 4 Polymerization of L-LA in solvent at 110° C. using Sn(Oct)₂catalyst system and hydroxy-end-capped polypropylene (PP-OH) as transferagent. M_(n) T Time Conv Mn M _(n SEC) ^(a) Example R(OH)_(n) LA/SnLA/R(OH)n^(c) R(OH)_(n) (° C.) solvent (min) (%) theo (PLA) M_(w)/M_(n)^(b) 23 PP-OH 1000 12.1 960 110 toluene 300 88 2 493 2 130 — 24 PP-OH1000 26.3 2 200   110 toluene 300 81 5 270 4 490 — ^(a) Number averagemolecular weights of the oligomers as determined by SEC in THF vs.polystyrene (PS) standards and corrected by 0.58. ^(b) Molecular weightdistributions calculated from SEC traces. ^(c)The ratio is not correctedto account for n number of OH groups.

The alcohols, multi-ols or amines group incorporation was confirmed by¹H and ¹³C NMR and GPC. Using, the Sn(Oct)₂ precursor, varying thecompound to alcohol, amine or multi-ol, revealed the versatility of thisapproach, allowing the preparation of accordingly end-functionalisedHO-PLLAOR polymers.

PP-PLA Properties

Blends of PP and PLA are known to exhibit heterogeneities due to polymerincompatibility (polymers are not miscible with each other). Example 23from Table 4 is blended with a metallocene based polypropylene resin (MR2001, Melt Index=25 g/min) and a PLA homopolymer prepared by ROP (MeltIndex=15-30 g/min) : blend ratio=40/40/10(wt %) PP/PLA/PP-PLA. A purePP/PLA blend (50/50) is prepared as comparison. The blends are done at200° C. and 100 rpm in a Haake micro-compounder.

The thermal properties (DSC curves obtained with a heating/cooling rateof 20° C./min between 20° C. and 220° C.) of the resulting materials areshown in FIG. 1 (PP/PLA 50/50) and FIG. 2 (PP/PLA/PP-PLA 40/40/10). Theyshow an improved compatibility for the blend containing PP-PLA with adifferent melting profile compared to the PP/PLA blend.

After staining with RuO₄, the material was analyzed by Scanning ElectronMicroscopy. FIGS. 3 and 4 show the PP/PLA 50/50 and PP/PLA/PP-PLA40/40/10 blends respectively.

These results show that the addition of PP-PLA to the PP/PLA mixtureimproves the compatibility of the 2 materials.

1-14. (canceled)
 15. A block copolymer comprising: at least onecompound, wherein the compound is a polymer selected from the groupconsisting of polypropylene, polyethylene, poly (L) lactic acid, poly(D) lactic acid, poly (D,L) lactic acid, polysiloxane, polybutylenesuccinate, polytrimethylene carbonate, polyester, poly ether,polystyrene, polyisoprene, polycarbonate, polyalkylenecarbonate,polyvinyl alcohol, polyurethane, and polyacrylate, wherein each polymercontains n number of OH and/or NH₂ group(s), wherein n is an integergreater than or equal to 1, wherein${\frac{{Moles}\mspace{14mu} {of}\mspace{14mu} {Lactide}}{\left( {{Moles}\mspace{14mu} {of}\mspace{14mu} {Compound}*n} \right)} \leq 70};$and one or more lactic acid chains, wherein each lactic acid chain isbonded to one of the polymers, wherein${\frac{{{Mn}\left( {{lactic}\mspace{14mu} {acid}\mspace{14mu} {oligomer}} \right)} - {{Mw}({compound})}}{n} \leq {10\; 100\; g\text{/}{mol}}},$wherein Mn(lactic acid chain) is measured by size exclusionchromatography, and wherein n is the number of OH and NH2 groups presentin the compound, wherein the block copolymer is made by a processcomprising: contacting lactide monomers in the presence of a catalystwith the at least one compound to form the block copolymer comprisingthe lactic acid chain; wherein reaction is performed at a temperature ofat least 70° C.; quenching the reaction so that the lactic acid chainsformed by reaction consist of 70 or less of the lactide monomers,wherein the quenching agent is an acid chloride having a formula ofCl—CO—R⁹, wherein R⁹ is 1-pentenyl or aminoethyl.
 16. The blockcopolymer according to claim 15, wherein said process is performedwithout solvent.
 17. The block copolymer according to claim 16, whereinsaid process is performed at a temperature of 110° C. to 190° C.
 18. Theblock copolymer according to claim 15, wherein the catalyst is anorganometallic catalyst.
 19. The block copolymer according to claim 15,wherein said catalyst has general formula:M(Y¹, Y², . . . Y^(p))_(q), wherein M is a metal selected from theelements of columns 3 to 12 of the periodic table of the elements, aswell as the elements Al, Ga, In, Tl, Ge, Sn, Pb, Sb, Ca, Mg and Bi;wherein Y¹, Y², . . . Y^(p) are each substituents selected from C₁₋₂₀alkyls, C₆₋₃₀ aryls, C₁₋₂₀ alkoxys, C₆₋₃₀ aryloxys, other oxides,carboxylates, and halide groups as well as elements of group 15 and/or16 of the periodic table; wherein p and q are integers between 1 and 6.20. The block copolymer according to claim 19, wherein the reaction isperformed at a temperature of at least 140° C.
 21. The block copolymeraccording to claim 15, wherein n is at least
 2. 22. The block copolymeraccording to claim 15, wherein said compound is a polymer that isselected from the group consisting of: polypropylene, polyethylene, poly(L) lactic acid, poly (D) lactic acid, poly (D,L) lactic acid,polysiloxane, polybutylene succinate, polytrimethylene carbonate,polystyrene, polycarbonate, polyalkylenecarbonate, polyvinyl alcohol,and polyurethane, wherein the polymer contains n number of OH and/or NH₂group(s), and wherein n is an integer greater than or equal to
 1. 23.The block copolymer according to claim 15, wherein the compound is apolymer selected from the group consisting of: polypropylene,polyethylene, polysiloxane, polybutylene succinate, polytrimethylenecarbonate, polycarbonate, polyalkylenecarbonate, polyvinyl alcohol,polyurethane, and polyaminoacid, wherein the polymer contains n numberof OH group(s), and wherein n is an integer greater than or equal to 1.